First thing to do is set up your equation:
45/x = 20/100
Cross multiply
4500 = 20x
And divide by 20
Answer: 225 people were surveyed
The number of permutations of the 25 letters taken 2 at a time (with repetitions) is:

The number of permutations of the 9 digits taken 4 at a time (with repetitions) is:

Each permutation of letters can be taken with each permutation of digits, therefore the total number of possible passwords is:
Answer:
solve simultaneously
start by labeling them equation 1 and 2 then choose whether you want to make x or y the subject from knew of the equations
Step-by-step explanation:
the slope of a line is always the factor of x.
here : 1/2
it is the ratio y/x indicating how many units y changes, when x changes a certain angina amount of units when going from one point to another.
a perpendicular slope puts x and y upside-down and flips the sign.
here : -2/1 = -2
so, the equation looks like
y = -2x + b
b is the y-intercept, and we get this by putting the x and y coordinates of the given point into this equation and solve for b :
-1 = -2×-2 + b
-1 = 4 + b
b = -5
the full equation is therefore
y = -2x - 5